Improved Qubit Control with Phonons

For quantum computers to leave the laboratory, researchers will have to overcome many challenges, including some concerning how to move information through a system. Qubits are the basic unit of information in a quantum computer, and can be made of ions, photons, or electrons. As reported by Springer, researchers at Zhejiang University, Hangzhou, China, and the Center for Computational Science and Engineering at the National University of Singapore have found a new way to transport electron qubits.

Key to the discovery was the use of phonons. Phonons are the quanta of vibrations, similar to how photons are the quanta of light. The researchers first confined electrons in what is called a Double Quantum Dot (DQD) and used a nanomechanical resonator to create phonons. These phonons then coupled with the electrons. When the researchers caused the electrons and phonons to decouple, they found it was possible to induce the electrons to tunnel from one quantum dot to the other, in the DQD. This only happened when an integer number of phonons could be created by the extra energy of the two quantum dots in the DQD. However, when the coupling was particularly strong, the researchers found the electrons were more strongly confined within the DQD. This means phonons can be used to control electron transport.

While quantum computers are still a ways off, this research will help in the design and creation of electron-based quantum computers.